1. Field of the Invention
The present invention relates to a vibration isolating apparatus which is interposed between a vibration generating portion and a vibration receiving portion to absorb vibrations by means of the fluid resistance of a liquid passing through an orifice.
2. Description of the Prior Art
There has already been proposed one type of vibration isolating apparatus which may be employed as an engine mount, cab mount, body mount or the like for an automobile, in which a liquid chamber is partitioned into two small liquid chambers by an intermediate membrane, and an orifice is provided at this partition portion to produce fluid resistance when a liquid passes through the orifice (see Japanese Patent Laid-Open Nos. 131072/1977 and 117704/1978).
This conventional vibration isolating apparatus is provided with a shaft which extends through the partition portion for transmitting the expanding and contracting force of one small liquid chamber to the other small liquid chamber to make the latter expand and contract so as to enhance the vibration damping effect. The orifice is defined between this shaft and the portion member so that, when the small liquid chambers are expanded and contracted, the liquid is rapidly passed through the orifice.
The above-described conventional vibration isolating apparatus suffers, however, from the following problem. When vibrations act in a direction which is different from the direction of the axis of the shaft, the gap between the shaft and the partition, that is, the size of the orifice, is changed, which means that it is impossible to damp vibrations at a desired frequency, disadvantageously.